Plum curculio’s distribution at different heights within a peach orchard

Plum curculio (PC), Conotrachelus nenuphar (Herbst) is a key pest in Southeastern peach production by infesting fruit and decreasing yield. To develop reliable PC monitoring tools and establish successful PC management programs, understanding the pest’s behavior is important. The objectives of our research were to (1) determine PC’s distribution at different heights within a peach orchard, and (2) investigate whether PC in Southeastern peaches exhibit the “edge effect”, where more PC are present next to a forested border than in the center of an orchard. We deployed black pyramid traps at three different heights—placed 0 (low), 120 (medium) and 240 (high) cm above the ground along four transects, going from the edge of the forest towards the center of the orchard. Sampling lasted from mid-Mar to Oct in 2019. We found significantly more PC in low traps early in the season and high numbers of PC flying within the peach orchards throughout the season, suggesting that a combination of trap heights may be needed for PC monitoring. The edge effect only occurred late in the season when PC were seeking overwintering sites in the forest, whereas the edge effect was absent early in the season. This finding suggests that PC may overwinter both in the orchard and adjacent forest.